The present invention relates generally to fireworks and, more particularly, to a fireworks aerial display shell, such as a consumer fireworks aerial display shell, of the type intended to be launched from a launch tube of a mortar and to a method of using the aerial display shell to create a pyrotechnic, visual effects display when launched to a desired altitude.
As used herein, “consumer fireworks” has the meaning set forth in Title 27, Code of Federal Regulations, Section 55.11, as small fireworks devices designed to produce visible effects by combustion and which comply with the construction, chemical composition, and other requirements of the U.S. Consumer Product Safety Commission, as set forth in Title 16, Code of Federal Regulations, parts 1500 and 1507.
Consumer fireworks aerial display shells of the type intended to be placed within and then launched from a launch tube of a mortar are well known and are commonly referred to as reloadables. One type of such shells is commonly referred to as ball shells and another type is referred to as canister shells.
A multiple effect or break ball shell is disclosed in U.S. Pat. No. RE38,592 and is characterized by multiple spherical balls that each contain an effects charge of stars and a burst charge. The outer casings of adjacent balls are joined together, such as by a wrapping of glue-soaked threads, and timing or delay fuses extend through aligned holes in adjacent balls to carry an ignition fire from the effects charge in one ball to the effects charge in the next ball. A lift chamber at one end of the ball assembly contains a lift charge connected to a lead fuse, commonly referred to as a shell leader. The lift charge is also connected to a timing fuse that communicates with the effects charge in the lowermost ball shell. The multiple effect ball shells are launched by placing them in a launch tube and lighting the lead fuse, which burns and then ignites the lift charge to propel the balls shells upwardly out of the launch tube to an altitude. The burning timing fuses then cause sequential ignition of the break charges to produce the pyrotechnic visual effects display.
An example of a canister-type aerial display shell is disclosed in U.S. Pat. No. 6,912,958. The aerial display shell disclosed in that patent has a cylindrical casing and a long lead fuse that ignites a lift charge housed at one end of the casing. When ignited, the lift charge propels the aerial display shell upwardly and out of the launch tube. The aerial display shell includes an effects charge, comprising stars and a burst charge, which is separated from the lift charge in the casing and produces the pyrotechnic visual effects display. A timing or delay fuse is used to ignite the effects charge. The burning lift charge ignites the timing fuse, which burns while the aerial display shell is being propelled through the length of the launch tube and during its upward ballistic travel outside the launch tube. The burn time of the timing fuse is set to allow fire to be communicated to the effects charge once the aerial display shell has reached or nearly reached the apex in its ballistic trajectory.
Some enthusiasts prefer balls shells because they have generally been thought to provide a more symmetrical pyrotechnic display than is normally achieved by canister shells. Other enthusiasts prefer canister shells because they are generally thought to provide a louder noise or effect that accompanies the visual pyrotechnic display. Canister shells are generally considerably easier to manufacture than balls shells because their outer cylindrical casing can be pre-formed and presents open ends through which the various internal components can then be sequential loaded and tightly packed. Highly compressing the effects charge can lead to the louder noise that is typically associated with canister shells.
Because the outer casings of ball shells are spherical, they lack the open ends through which the internal components can be readily loaded and tightly packed. As a result, the outer casings of ball shells, in one conventional process, have been made by applying pre-glued paper around the pre-formed pyrotechnic effects charge. In another process, the outer casings of ball shells are pre-formed as separate hemispheres that are separately loaded and packed before being joined together, such as with glue, to form the spherical ball shell. The making of multiple effects ball shells presents additional challenges in securing the spherical surfaces of the balls to each other and in routing the timing fuse from the effects charge in one ball to the effects charge in the adjacent ball. In any event, the process of making ball shells generally requires considerably more labor and skill than the process of making canister shells. As a result, far fewer factories presently produce ball shells than those that produce canister shells. A need has thus arisen for a way to address the preference of some enthusiasts for the appearance or multiple effects of ball shells without the attendant challenges that presently accompany the manufacture of ball shells.